I am grilling a 5 lb standing rib roast in my gas grill with my rotissere burner and spit. Can I add sum lump charcoal in the sides of my grill, possibly in smoker boxes to increase the heat and add some flavor? Do you think this a good idea or not worth the trouble?

Directly on the flames may be dangerous as your grill's firebox isa not designed for high concentrated heat. Charcoal probably won't burn well in a smoker box. If you want to add flavor, add soaked wood chips or chunks either in a smoker box or in foil pouches.

THer is much controversy about whether charcoal adds any significant flavor. Wood smoke and vaproizing meat juices do most of the flavoring IMHO.

Sure you can. I do it all the time on my gas grill. Whenever I use the rotisserie burner, the grill won’t allow me to light up any other burner. I place a small loaf foil pan in the corner of the grill add 3-4 pieces of coals and a hand full of soaked wood chips. This usually has no effect on the heat, but the wood will add a lot of flavor. I think you’ll get sufficient heat from the rotis. burner. But if you think the roast is getting too browned on the outside, then turn off the rotis. burner and turn on the main burners on low. If you have several burners on your grill, then turn on the ones on either side of the roast.

So, you're using the charcoal as a heat source for the wood chips? Never thought of that, but I've never had a grill with a rotiss burner. When I had a rotiss, I used the main burners. Never ocxcured to me that they would lock out the other burners. Sounds like one of those "improvements" that make simple things like adding wood smoke more difficult. I guess if you get one of these things, you need to spring for the extra bucks to get a special smoker burner.

For my part, I have found that I don't miss the rotiss attachment at all. I believe that I can get the same or better results using other techniques.